1. Field of the Invention
The present invention relates to a snore detection method and a snore detection device.
2. Description of Related Art
Detection of snoring during sleep makes it possible to diagnose one's health state or to prevent the occurrence of snoring. Already proposed are a snore detection device for judging whether snoring occurs based on vibration (pressure variations), generated by the human body with respiration, and another snore detection device for judging whether snoring occurs based on snoring sound (JP-A No. 184948/1995).
According to FIG. 13, however, an investigation of the phase relationship between pressure data variations obtained by measuring vibration generated by the human body with respiration and sound data variations obtained by measuring snoring sound reveals that there exist following cases: the time at which the peak P1 of the pressure data appears corresponds to the time at which the peak P2 of the sound data appears, as seen in FIG. 13(a); the time at which the peak P2 of the sound data appears falls behind the time at which the peak P1 of the pressure data appears, as seen in FIG. 13(b); the time at which the peak P2 of the sound data appears is earlier than the time at which the peak P1 of the pressure data appears, as seen in FIG. 13(c). This is because the magnitude of snoring sound is varied in accordance with speed of respiration air flow or airway state while the magnitude of pressure data is varied in accordance with a posture of the sleeping human body. Accordingly the appearance of the peak of the sound data is not always in synchronism with that of the peak of the pressure data.
Thus a snore detection device for judging whether snoring occurs based only on the variations of the pressure data, and a snore detection device for judging whether snoring occurs based only on the variations of the sound data are low in accuracy, and are likely to erroneously judge vibration or sound generated by causes other than snoring as the occurrence of snoring, as the case may be.